1. Field of the Invention
The present invention relates to an image processing system, an image processing apparatus, an image forming apparatus, and a computer-readable storage medium.
2. Description of Related Art
There has been a method of providing an image processing apparatus, such as a print controller, between a printer and equipment (e.g. a personal computer (PC), a portable terminal, or the like) to output an instruction (print job) for making the printer perform an image formation, when the image formation is performed by an image forming apparatus, such as the printer. When the print controller receives the input of a print job, the print controller performs rasterizing processing to generate image data of a bit map, or the like, on the basis of the page description language (hereinafter referred to as “PDL”) included in the print job, and outputs the generated image data. The printer forms an image on the basis of the image data input from the print controller.
FIG. 12 is an explanatory diagram showing an example of the configuration of a print job.
The print job of the present example comprises a printer job language (PJL) and a PDL.
The PJL is the information to describe instructions pertaining to an image formation in a command format. As one of the contents determined by a PJL command, a content pertaining to the color adjustment data to be applied to the image data generated by a PDL may be cited.
FIG. 13 is a diagram showing an example of the color adjustment data.
Each piece of the color adjustment data shown in FIG. 13 includes four sets of gamma conversion tables, each showing a relationship between input tone values and output tone values, and each set corresponds to each color of cyan (C), magenta (M), yellow (Y), and black (K), respectively.
Each of the gamma conversion tables shown in FIG. 13 shows the relationship between input and output tones of each color of 256 tones, i.e. 8 [bits] colors.
As shown in FIG. 13, each of the gamma conversion tables of each set is the data capable of being expressed by an independent gamma characteristic curve for each color, and the locus of each gamma characteristic curve corresponds to gamma values of each color.
The gamma values are the values indicating the intensities in each gamma characteristic curve. When the gamma values are plus, a curve (for example, the uppermost curve of those in ADJUST2 shown in FIG. 13) is shown in which the output tone values (on each ordinate axis shown in FIG. 13) are relatively larger than the input tone values (on each abscissa axis shown in FIG. 13). On the other hand, when the gamma values are minus, a curve (for example, any one of the curves in ADJUST1 shown in FIG. 13) is shown in which the output tone values are relatively smaller than the input tone values. Moreover, the size of each of the curves changes according to the magnitude of the absolute value of each of the gamma values. The smaller the absolute value of each of the gamma values is, the smaller each of the differences between the input tone values and the output tone values is, which makes the curves smaller. The larger the absolute value of each of the gamma values is, the larger each of the differences between the input tone values and the output tone values is, which makes the curves larger.
As shown in FIG. 13, a color adjustment data name is given to each piece of color adjustment data, and, for example, the description of “@PJL SET COLORADJUST=ADJUST1” shown in FIG. 12 indicates that the color adjustment data having the color adjustment data name of “ADJUST1” shown in FIG. 13 is applied.
As shown in FIG. 13, the adjustments of colors based on color adjustment data are the processing in which each color of cyan (C), magenta (M), yellow (Y), and black (K) is independently subjected to a tone adjustment, and are different from the processing pertaining to a color space conversion by the application of an ICC profile, or the like.
The PDL is a command to instruct the print controller to render an image. The print controller interprets the content of a PDL command and performs rasterizing processing to generate image data.
Conventionally, print controllers have generated image data that had already been subjected to a gamma adjustment by the use of color adjustment data at the time of performing rasterizing processing. That is, the image data generated by the conventional print controllers only includes color information in a state where the gamma adjustment based on the color adjustment data has already been performed.
Accordingly, as described in, for example, Japanese Patent Application Laid-Open Publication No. 2006-82482, even when the rendering content given in the instruction by a PDL is the same as that of a prior print job, the print controller performs rasterizing processing again to generate new image data and inputs the generated new print data to a printer, in a case where the color adjustment data specified by a PJL is changed to newly perform printing (hereinafter referred to as “reprinting”).
However, because the rasterizing processing is performed at each event of reprinting in which different color adjustment data is used when image data is generated by the conventional print controllers described above, the throughput of the print controller is obliged to be considerably spared for the reprinting based on the different color adjustment data. Further, the throughput capable of being assigned to the rasterizing processing based on the other print jobs is consequently decreased to deteriorate the responses of the print controller. Moreover, a configuration to perform gamma adjustment is sometimes provided in a printer to perform the gamma adjustment of image data input to the printer.
Here, when the image data in the state of being subjected to the application of gamma adjustment based on color adjustment data is generated at the time of performing rasterizing processing, the color information of the image data before the gamma adjustment based on the color adjustment data, that is, the tone information of the image data in the state where no gamma adjustment based on the color adjustment data is added (hereinafter sometimes referred to as “original tone information”) is lost.
Consequently, when the image data in the state of being subjected to the application of a gamma adjustment based on color adjustment data is generated at the time of performing rasterizing processing, the gamma adjustment in a printer happens to be performed for the image data which has already been performed with the gamma adjustment based on the color adjustment data, and consequently the gamma adjustment for the original tone information cannot be performed. That is, it is resulted in that the image data after the color adjustment based on the color adjustment data is further subjected to a color adjustment, thereby the accuracy of color reproduction based on the original tone information is reduced.